The inventors are in the business of hauling grain and seeds with tractors and trailers. Recently they have been hauling sunflower seeds. Sunflower seeds have a high bulk to weight ratio. When a trailer is fully loaded with sunflower seeds it is carrying less than 70% of its licensed load weight. To substantially increase profitability the inventors have experimented with different methods of increasing the volumetric capacity of their trailers.
One method of increasing the capacity is to attach a peripheral fabric extension to the top portion of the walls of the trailer. A collapsible peripheral extension can be raised when hauling load and lowered to reduce drag and conserve fuel when driving unloaded. The problem with this solution is that the fabric extension lacks sufficient strength to support lateral load produced by the shifting cargo. Sustained vibration and rapid deceleration both result in large lateral loads on the fabric extension.
The inventor has found that only when the fabric is maintained taut that it is able to sustain significant lateral loading. Within this specification fabric is broadly defined to include any plastic or other material which is capable of centrally flexing.